Reversing-switch.



G. H. WHITTINGHAM.

REVBRSING SWITCH. APPLICATION FILED NOV. 2, 1908. I 965,671 Patented July 26, 1910.

2 SHEETS-SHEET l.

Juf,

G. H. WHITTINGHAM.

REVBRSING SWITCH.

APPLIUATION FILED Nov. z, 190e.

965,671', Patent-,ea July 26,1910.

www. (i 47V. ZZzQ/M a@ mm amm,

ras Parana" orare.

GEORGE H. WHITTINGHAM, OF BALTIMORE, MARYLAND, ASSIGNOR T MONITOR MANUFACTURING COMPANY OF BALTIMORE CITY, A CORPORATION OF MARYLAND.

REVERSING-SWITCH.

Specification of Letters Patent. i Patented uly 26, 1910.

Application filed November 2, 1908. Serial No. 460,666.

To all 'whom 'it 'may concern:

Be it known that l, vGuiones H. l/Vnrr- TINGHAM, a citizen of the'United States, residing at Baltimore, in the State of Maryland, have.I invented certain new and useful Improvements in ReversingSwitches, of which the following is a specification.

YrI`his invention relates to a simple form of reversing switch for electric motors, which may be operated by opening and closing push button switches and it comprises means whereby lthe motor may be operated at iull speed in one direction and at a reduced speed in the opposite direction.

The invention is particularly applicable to motors used for operatingcertain types of printing machinery and other machines which have to be started and stopped frequently and where it is desirable to run the machine forward at one speed and backward at a reduced speed.

The inventio-n comprises two movable switch members normally connected to one side of the supply circuit, and also connected to the armature terminals, and electrically controlled means for moving either one of these switch members so as to disengage it from one side of the supply circuit and connectit to -the opposite side, to con'- trol the direction of movement of the motor.

It also comprises a brake-resistance which is connected to one side'ot the suppl circuit and which is also used as a regu ating resistance for controlling the speed of. the motor. n

In the accompanying` drawing,- Figure 1 is a diagrammatic view illustrating the mechanism for operating an electric motor at ullspeed in one direction and at a reduced speed in the opposite direction, the parts being shown in normal positions; Fig.

. 2 is a similar view illustrating the operation of the device shown in Fig. 1; Fig. 3 is a similar view of a mechanism for operating the motor at the same speed in both directions; and, 4 is a similar Aview of the device shown in Fig. 3, illustrating its operation, and also showing an attachment for preventing the operation of more than one switch magnet at a time.

Referring to Figs. 1 and 2 of the draw-V ing, V1 and 2 indicate a pair of contact memberselectrically connected together by the conductor 3, which latter is connected to the side 4 of the lsupply circuit. These contact members 1 and 2 are arranged above solenoids B and F, respectively,- and immediately below the solenoids are arranged contact members 5 and 6 which latter are connected together by a conductor and a brake-resistance R and they are also connected to the side 7 of the supply circuit through a suitable starting device 8 and a conductor 9, the latter, as shown in Figs. 1 and 2, being connected to one end of the brake-resistance R. The core 11 of the solenoid B has at its upper and lower ends contact members 12 and 13 which are secured to the core by copper conducting rods 14 and 15, respectively, and the core 16 of the solenoid F carries at its upper and lower ends contact members 17 and 18 similarly secured to said core. The core 11 with. its .attached contact members or surfaces constitutes a movable switch member b and the core 16 with its attached contact surfaces constitutes a switch member The switch member b'normally rests upon the contact member 5 and the switch member f normally rests upon the contact member 6, so that these switch members are both normally connected to one side 7 of the supply circuit through the conductors 9 and 10. The terminals or brushes of the armature a of themotor M are connected by conductors 19 and 20 to the switch members b and f, respectively, the end portions 19a and 2()E of said conductors being flexible and secured to the switch members as shown. Both armature terminals or brushes are therefore normally connected to one side of the supply circuit. The motor shown in the drawing is a shunt wound motor and its field coils are shown permanently connected by the conductors 21 and 22 to the sides 4 and 7 of the supply circuit. The coils of the solenoids B and F may be connected in any suitable way to asource of current supply. As shown in the drawing one terminal of each coil is connected by a conductor 23 to 100 a conductor 24 which leads to the side 4 of the supply circuit, and the other terminals of the coils are connected by conductors 25 and 26 to the side Tof the supply circuit,

suitable push buttons or other hand switches 105 b and f being provided for openin and closing thecircuits through the so enoid coils.

The operation of the device showninFigs.

1 and 2 is as'follows: Normally the mem# 11C' l one side -of the,supptlly17 v. push-button or hand switch b is closed, the

switch member b is lifted by the coils of the solenoid B until the contact surface 12 engages the' contact surfaceo' 1,,as 'shown in Fig. 2. This, it will be seen; disconnects the amature conductor 19 from the side 7 of the suppl circuitand connects it withl lthe side 4, W ile Y still remains connectedto the side `7 of the the armature conductor 20 suppl circuit, through the-brake-resistance R. Clii'rrentwill then flow from the side 7 through the brake-resistance and contacts l Y 6 and 18 and conductorA 2O to the armature and thence through conductor 19, switch/ membelb., contact l and conductor 3. to the side 4 of the su the rotation. o the motor in one direction at a speed less than its normal speedbecaus'e yao armature, When the switch 1) the brake-resistance R is in series with the is opened the switch member Z) drops by gravit enga ement with the contact-sur ace 1 at the slde 4 of the supply circuit and into engagement with the J.contact surface 5 at the opposite side of the supply circuit. As the brake-resistance R is included between the lcontact members 5 and 6, it will be seen that when the switch member b dro s the'current generated by the momentum o the armature will flow through the brake-resistance and cause a prompt stop age of the motor. The field coils s are pre erably left connected to bothsides of the supply circuit so as to insure a strong field for braking urposes. When the switch f, Figs. 1 and 2, 1s closed,

the switchmcmber f moves out of engageyment with the contact 6 and into engagement with the contact 2 thereby disconnecting the armature conductor 20 from the side 7 of the supply circuit and connecting it with the side 4,y While the armature conductor 19 remains connected to the side 7 of" the supply circuit'. lAs t-he connection between the contacts G and 18 is then broken, no current can iiow through the brake-resistance R and hence the armature will' receive current from the side 7 of the supply circuit, through conductors 9 and 10, contact 5, switch member b and conductor 19, and the current will flow from the armature through conductors 20, switch member f contact 2, and conductor 3 to the side 4 .ot the supply circuit, at a hlgher speed than before and in a reverse direction. When the switch f" is o ened the solenoid F is denergized and t e switch member f drops, breaking connection with the side 4.ofv the supply circuit and establishing connection with the opposite side of the supply circuit and also comply circuit. This will cause.

out ofy thus operating the motor pletingitheV connection between the brakeresistance and the armature conductor 20 so that^.the braking action may then take place while the motor is moving under its own momentum. I't cw1ll be noted that in this reversing switch the armature is normally connected to one side of the supply circuit'I through bothv movable switch members and that by simply vmoving one of .said members over to the other side of the supply circuit the circuit is completed through the armature, one or the other terminal of which always remains connected to one side' of theL supply circuit through one, or the other. of the movable switch members inthe normal operation of the apparatus. If, by chance, some one should close one of the push button switches while the other push button switch is closed and the motor isin operation, this would merely result in connecting both of the electricallyvcontrolledi switch members to the side 4 of the supply circuit and disconnectmg them vfrom the side 7 which would result in stopping the motor and could cause no injury to the motor. Ordinarily this would not occurl where the rpush button sistance is' omitted from the. armature circuit while the motor armature is running in y one direction, andis included in said circuit while the motor is running in. the opposite direction, thus giving a full speed in one direction and a reduced speed in the opposite direction.

By connecting the wire 9, in Figs. 1 and 2, to the Wire 10, at the right of the resistance R, instead of at the left, it will be evident that the operation, with respect to the speeds, will be reversed, the brake-resistance being then included in the armature circuit when the push button f is closed and being eliminated from the armature circuit when the push button b is closed. If the wire 9 is connected to the center of the brake-re sistance, as shown in Figs. 3 and 4, the speed of the motor will be the same in both directions of rotation, being slightly less than the normal full speed because of thc fact that one-half of the brake resistance will be in the armature circuit while the motor is being driven. As a brake resistance, to be effective, in a brake circuit, must be a comparatively low resistance, the interposition of one half of this resistance in the armature circuit, while the motor is being driven' mature when the motor arma-ture is operating undr its own momentum. x

In Fig. 4 the push button 1s shown 1n closed position and the `solenoid F has lifted terial (Fig. 4) havin its core, the connection between the core and the side 7 of the supply circuit being thereby broken and the connection between said core and the side 4 of the supply circuit being thereby established, and as the` core is connected to the armature of the motor, the current to the armatureiiows from the side Tof the Supply circuit through the starter and conductor 9, thence through the section 'l' of the resistance R, through conductor 10 to the contacty 5, thencethrough contact 13, conductors 19 and 19 to the armature a, thence through conductors 2O and 20",- core 16, contacts 17 and 2, and'conductor 3 to the side 4 of .the supply circuit. The motor will therefore run in one direction with the` section r of the brake resistance in circuit with the armature., When the switch f opens the core 16`drops, thereby disconnecting the armature from the side 4 of the supply circuit and connecting theentire-brake-resistance in series with theparmature. If the push button bf is now vclosed the solenoid'B will lift its core thereby disconnecting the. latter from the side 7 of ther/supply clrcuit and connecting it to the side 4 of the supply circuit, so that the current will then iiow from the side. 7 through conductor 9, ref sistance section 1", contacts and 18, conductors 20 and 20, armature a conductors 19 and 19a, contacts 12 and 1 and conductor 3 to the side 4 of the supply circuit. When the push button b is opened the Acore 12 drops, breaking its connection with the side'4 4 of the supply circuit and establishing Iits connection with the lside 7 and also connects: ing the brake resistance in5 series With'the.

armature.

. In order to prevent one'solenoid from' bei i ing operated while the core of the other so eno1 d is raised, a suitable mechanical connection may be made between the cores, such for instance as the centrali pivoted bar 3D made wholly or partly o? insulating maits ends projecting over the collars 31 an 32 on the rods 14 of the cores 11 and 16a I the ,push button' f' is closed, as shown infFi 4, the collar 82" is raised by the core of t e solenoid F andu this collar, 32, lifting one end of the lever 30, depresses the opposite end, which` extends over the collar 31 movable with the core 11. As the core 16 is then in a more el'ective osition within 7the coils of the solenoid d? coils of the solenoid B, the core 11 cannot lift, if the switch E is closed after the push button f is closed and the core 16 is lifted.

while the bar.

than is the core 11 within the` Similarly if the push button b isiclosed ush button f is open and the latter switc is then closed, the core 11 `will hold the lever in position to prevent the4 core 16 from lifting. Any suitable mechanical device may be used for the purpose of preventing more than one of the solenoids from being operated 'at one time.

It is evident .that the ctmcl'uctoi` Sima `v`,be

a metal bar having suitable contact sur aces 1 and -2 above the solenoid. IVhent-he reversing switch fis used. with small motors having a com aratively -high armature resistance, the.- rakeresistance RV may be omitted, in which case thecontact members.

5 and 6 would be connected directly together by the conductor`10, which may WhatIclain iszl' 1 1. .In a reversin switch for electric moaf metal tors, the combinat1on withf a motor having?v shunt'field windings, of two contact memy bers connectedto one side of the supply circuit, a resistance connected between said contact members, two switch members connected to the armature terminals -and normally engaging said contact members, and means for isengaging either of said switch inembers from said contact members and for con necting it to the opposite side of the supply circuit. Y

2. In a reversing switch for electric motors, the combination with a motor having shuntield windings, oftwo contactmembers connected to one side'of the supply circuit, a resistance connected between said contact members, two switch members connected to the armature terminals and normally engaging ,said contact members, and electroma netic means for disengaging either ogf sai switch members from said contact members and forconnecting it to the opposite side of the supply circuit.

'3. In a reversing -switch for electric motors, ltwo contact-members connected to one side of the supply circuit, a brake-resistance side of the' supply circuit, a brake-resistance connected vbetween said contact members, two switch members connected tothe armature terminals and normally engaging said contact-members, and electromagnetic means for disengaging either of said switch members from said contactmembers and for connecting it tothe opposite side of the supply circui. y y

5. In a reversing switch for electric mo# two switch members connected to the arma- 6. In a reversing "connected between said contact-members,

ture terminals and normally engaging said contact members, and separately controlled devices for disengaglng said members from said side of the supply circuit and for connecting them to the opposite side 0f the supply circuit. 5

switch for electric motors, twoy contact-members connected to one sideof the supply circuit, a brake-resistance two switch members connected to the armature terminals and normally engaging said contactA members, and separately controlled electroma etic devices for disengaging said mem vers Vfrom said side of the supply circuitv and for connecting them to the opposite side of the supply circuit.

7. In afreversingv switch for electric motors, twocontactl members or surfaces conn'ected to--one side of the supply circuit, a /brakeJresistance connected between said surfaces,v two inde endently movable switch m'embersknormal y engaging said surfaces and connected to the'armature terminals',

and contact surfaces connected to the opposite side of the supply circuit and adapted to be engagedby said switch members when the latter are moved from'normal' positions.

8. In a reversing switch for electric motors, a pair lof contact surfaces connected to Ione side of the "supply circuit, an opposing pair of'eontact surfaces connected to t 1e og! posite side ofthe supply circult, indepen ently movable switch members arranged be'- twe'en said pairs of surfaces and 'normally engaging one pair of surfaces,a brake-resistance connected between of surfaces, and electrical connections between said switch members and the armature terminals. Y

' 9. In a reversing switch for electric motors, a pair of contact surfaces connected to one side of the supply` circuit, an opposing pair of contact surfaces connected to the ogposite side of the-supply circuit, indepen ently movable switch members arranged besaid latter pair.

tween. said pairs of surfaces and normallyv engaging one pair of surfaces, a brake-re. sistance connected between said latter pair of surfaces, electrical connections between said switch members and the armature terminals, and electromagnetic means for moving said switch members.

1Q. In a reversing switch for electric motors, two contact members, a brake-resistance connected between saidv 'membersi a supply circuit having one side connecte at one end of said brake resistance, two switch' members lconnected 'to the armature terminals and normally engaging said contact members, and means for lsengaglng elther ofl'said switch members from said contact miv members and for connecting it to the oppo-r Asite side of the supply circuit.V

11. In a reversing switch for electric motors, a. pair of contact members or surfaces connectedto one side of the supply circuit, a brake-resistance connected between sald surfaces, a pair of independently movable switch members normally resting upon said surfaces and electrically connected to the ar-v mature terminals, contact members or surfaces arranged above said switch membersund connectedto the opposite side of the supply circuit, and electrically controlled meansfor lifting said switch' members into engagement with said latter surfaces.

12. In a. reversing switch for electric mo- .tors, a pair of Vcontact members or surfaces connected to one side of the supply circuit, a

vbrake-resistance connectedv between said members, a pair of switch members nor- .mally resting upon said members or surfaces andelectrically connected to the armature terminals, independently controlled solenolds for lifting said members aways from said surfaces, and contact surfaces connecti ed lto the opposite side of the lineand arranged above ad normally out of contact with said switch members.

In testimony whereof I aiiix my signature,

in presence of two witnesses.

GEORGE H. WHITTINGHAM. Witnesses: y FELIX R. SULLIVAN,

A. Y. .IAVINa 

